The longer straws and the longer pipes produce a lower pitch.
Work Step by Step
It is helpful to look at Figure 21.5 when answering this question. The question is really asking how the length of a closed-end air column affects the natural frequency of the column. It turns out that the longer the air column, the lower the frequency and the pitch. Why? The longer straw/pipe has a longer-wavelength standing wave. The wave speed stays the same, and is equal to (wavelength)(frequency). The wavelength is longer, so the frequency is shorter. The air column resonates with the external stimulus. The pitch of the note falls as the straw/pipe becomes longer.